In this recent article in the Scientific American, we learn that astronomers have discovered 629 planets outside the solar system. NASA’s Kepler mission has discovered over 100 in an area of the Northern Hemisphere covering only 1% of the sky. Ten of these exo-planets are terrestrial, that is they are small planets with solid surfaces. I know of at least one of these that appears to have a triple-point temperature range: water can exist as ice, liquid and vapor. This is amazing and sobering news when one considers that we have only just begun our search for such planets and that we are as yet only searching in our own neighborhood.
Our own solar system is ripe for settlement and development. The moon and Mars are the two most likely candidates. The moon because of its proximity and Mars because it has an atmosphere and water. Once methods of interplanetary travel are established, the asteroids and the large moons of the outer solar system will be the next likely candidates. Eventually a space faring culture will develop off the Earth, a culture that sees the cosmos as its habitat. This culture will inevitably look to the stars and to b the many exo-planets as the next logical goals for settlement. Multi-generational missions to settle these new planets would not be inconceivable to people raised in such a culture.
We may eventually develop a means to break the light barrier, the cosmic speed limit postulated by Albert Einstein that nothing can move faster than the speed of light, the way we broke the sound barrier in the 1940’s. If so, these exo-planets will become stepping stones for us to further explore the universe as well a places for us to found settlements. In any case, the discovery of these exo-planets is akin in importance to the discovery that our own solar system planets were more than just points of light in the sky.